Posts Tagged ‘space’

Are there any other Earths out there? Is there another planet like ours, maybe one where we could live? One goal in the search for exoplanets, planets orbiting stars other than our own sun, is to find Earth-like planets. NASA’s Kepler mission just found the closest match yet!

This planet is called Kepler-452b. It’s not exactly a catchy name, but it’s informative: the name tells us the planet was found by the Kepler mission, and gives a number to the star system and a letter to each object. This planet got the letter “b” because it’s the second object found in the system, after the star.

A planet in its star’s habitable zone? We’ve found a few, but that’s still pretty cool—or rather, just the right amount cool for liquid water to potentially exist on the planet. This is the definition of the habitable zone. Without liquid water, we wouldn’t find a planet habitable, and in order to have liquid water, a planet would need to be warm enough for water not to freeze and cold enough for water not to boil. The temperature on the surface of a planet depends largely on its distance from its sun. The closer they are, the warmer the planet is. However, being not too close to and not too far from its star doesn’t tell you everything about a planet. It could be large or small, and made of all sorts of different materials. It could be dense and rocky like Earth or Mercury, or it could be fluffy and gaseous like Jupiter or Neptune.

So, being in the habitable zone isn’t enough to make a planet habitable. It would be hard to live on a planet without a surface you could stand on, so if you’re looking for a new planet to inhabit, pick out a rockier one. The size of the planet would also make a difference. The smaller a planet is, or even a moon for that matter, the harder it is to hold on to an atmosphere. Less mass means less gravity, which means less pull on the gases which make up an atmosphere. Gas particles can fly away over time until there are hardly any left. More mass means more pull, so it’s harder for particles to escape. So, more massive planets are more likely to have a thick atmosphere.

What about Kepler-452b? Where does this recent discovery fit in? It’s 60% larger than Earth in diameter, which is actually pretty close in size. For comparison, Kepler-452b is about 1.6 times the diameter of Earth, and Earth is about 1.9 times the diameter of Mars. Kepler-452b is considered a super-Earth in size. That’s what we call planets near in size to Earth, but on the large side.

While we know all this about Kepler-452b, there is also a lot we don’t know. We don’t know exactly what it looks like. We don’t know how close it is to actually being habitable. We certainly don’t know its whole story—yet. As technology improves, telescopes get better, and we think up cleverer ways to learn more about far-off places, we keep finding out more and more about distant worlds like this one.

How do astronauts move around out in space? They can use these, of course! Now if only we could get around like that on Earth… Something pretty close is the simulator at the Tech Museum of Innovation in San Jose, California.

Whenever I try to tell anyone what my job title is, nobody understands! I got so frustrated when I went to a geology conference and everybody kept asking me what my sign was! That’s not what I do! I’m pretty sure I’m a Virgo, but I have no idea what that means! The same thing happens when I meet astronomers. They keep assuming that I know stuff like the capital of Nebraska. I am not an astrologer and not a geographer, I’m an astronomer who is also a geologist.

Sometimes people just slip up even when they do know the difference. I had a pretty funny conversation with my grandparents when I tried to explain my job. Here’s pretty much how it went:

Me: “Grandpa, I’m not a cartoon artist. How’d we even get on that subject? I study things like volcanoes and craters. Geology. And I haven’t tried to draw Pluto. But there’s this spacecraft that’s headed to…oh, that Pluto.”

Grandma: “Oh, geometry, with the shapes!”

Me: “That’s mathematics, Grandma. I’m an exogeologist. That’s a combination of geology and astronomy. I look at space rocks.”

Grandma: “Like the astronauts got from the moon?”

Me: “Yes! Exactly!”

Grandpa: “That sounds fun.”

Me: “Yes, it ROCKS!”

Grandma: “So when will you be going to the moon?”

I hope this helps you to tell the differences between exogeology and completely different jobs. My grandparents finally understood after that long conversation, and I can usually get people to at least say it right. People who just haven’t heard of exogeology, or even geology or astronomy, are just part of the job. I can’t blame them really, although it is annoying. For now, I’m Petra Stone signing off. Exogeology ROCKS!

Want to know just what an exogeologist does all day? Well, maybe I can show you just how cool this job is!

When I start working for the day, the first thing I do is see if I’ve received any new data. This could be from other exogeologists or from different spacecraft. I sometimes even get rock samples to analyze. If I do, I’ll take them to the lab. There I’ll test the sample to find out its composition.

There are lots of tests I can do. I can test minerals for streak, hardness, cleavage or fracture, and of course note the color and shape of the crystals. For example, let’s say I was given a mineral sample to identify. It has cube-shaped crystals, and is gold in color. I rub it on a streak plate, and the streak is greenish black. I’ll scratch it with various tools and deduce that its Mohs hardness is 6. When I break it with a hammer, the place where it breaks is conchoidal (a distinctive curved shape). All these things put together tell me that my mineral is pyrite. If I were given a rock sample, there are a lot of various tests I could do to classify a rock, like cutting a thin slice and looking at it under a microscope.

Here’s a quick tip about classifying rocks: If it has bubbles, it’s got to be igneous. Those bubbles are called vesicles, and they’re made when gas bubbles are trapped inside a rock as it cools.

Some days I’ll go to an observatory to do research on a planet. I need to reserve the telescope ahead of time usually. When I used a telescope at the Kitt Peak observatory, I had to reserve the telescope years in advance! But it was worth it. I got some great photographs of Jupiter and a comet during my time at the telescope. I’ve used lots of different observatories, and it’s always been productive. Well, except for that one time when it rained… I had to cancel. I must have been really unlucky that time. But that’s the trouble with astronomy; sometimes you just have to wait for another clear night. At least every other time went well.

Other days I’ll get information from a spacecraft or lander! That’s my favorite part! Once, I got to help with the LCROSS mission and interpret data from the spectrometer. The goal was to find water, and we did! That ROCKS! Since Mars is my specialty, I’ve been receiving data from the Mars Odyssey orbiter, which maps the amount of chemical elements and their distribution. I loved working on that. Maybe I’ll get to interpret data from the upcoming Mars Science Laboratory (MSL). Part of the MSL’s mission will be to study the geology of Mars.

Well, I’ve always been an exogeologist really, it just wasn’t my job title until now.

I’ve always been interested in geology. When I was little some of my favorite books were about volcanoes, and I started a rock collection. As I got older I learned to recognize a lot of different minerals and rocks. I just loved learning about different kinds of lava and eruptions, and about which rocks were quartz and which were pyrite. As I got older I got more books, and my rock collection grew. I read about geology as much as I could. I had a lot of other interests along the way, and I’d focus on that for a while, but geology was always an interest of mine, even if it wasn’t the focus of my life.

I also watched a lot of episodes of NOVA and The Universe. I’ve also always liked space, but never as much as rocks. I mean, lots of kids want to be an astronaut at some point, or an astronomer, or something like that. Space is just too cool not to! Or at least that’s my opinion. I lived in a great place for both geology and astronomy (Tucson AZ), and just for fun my family visited places like the Kitt Peak and Whipple observatories.

At age 13, I started taking college classes at the local community college. By then I knew all about how geology could be used for things like analyzing moon rocks, and finding volcanoes on other planets. I thought it was really cool that Earth wasn’t the only planet to have geology! And of course, I wanted to learn more. I first took a geology class, because geology was my passion. The very last part of that class was about exogeology. And it was by far the best part. I got to see a picture of a hypothetical planet; I figured out what caused different landforms and how to use relative dating. I also got to look at craters on Earth. I later took an astronomy class, because I wanted to learn more about exogeology, but I didn’t know as much about the astronomy aspect. I knew that this was what I wanted to do. I was hooked, I wanted to be an exogeologist.

I then took more exogeology-related classes, which were mostly just geology or astronomy, one or the other, but they were all really interesting and I learned a lot. A few years ago I started working for NASA as an exogeologist. I’ve done all kinds of neat things since then, but my favorite is figuring out just what caused different formations (especially on Mars, that’s my specialty), like the Valles Marineris, or just rock strata. I love my job! I hope you’ll have just as much fun exploring exogeology as I do!